1. Field of the Invention
The present invention relates generally to systems from transmitting torque from a rotating driver to a rotational load. In another aspect, the invention concerns a method and apparatus for starting up a large compressor driven by a gas turbine.
2. Description of the Prior Art
Rotating drivers powering rotational loads are employed in many applications. For example, facilities that produce electrical power frequently employ a gas turbine to power an electrical generator. Further, liquified natural gas (LNG) facilities typically employ at least one gas turbine or electrical motor to power a refrigerant compressor.
When large, high-speed rotational loads are employed, it may be impossible to start up the associated driver while it is coupled to the load. In such a scenario, the most common solution is to decouple the load from the driver during start-up of the driver, and then somehow couple the load to the driver once the driver has reach normal operating speed. Obviously, a non-rotating load can not simply be abruptly mechanically locked to the driver while the driver is rotating at full speed.
In the past, large “starter” motors have been employed during start-up of large rotational driver/load combinations. The starter motors are used to bring the load up to operating speed so that it can be mechanically coupled to the driver. However, starter motors that are powerful enough to increase the rotational speed of the load from zero to full operating speed are very expensive.